Writing an Architect expression that formats a phone number from +1XXXXXXXXXX to (XXX) XXX-XXXX

What You Will Build

• One sentence: This tutorial demonstrates how to construct a Genesys Cloud Architect expression that converts an E.164 formatted phone number into a standard North American display format.
• One sentence: This uses the Genesys Cloud Architect Expression Builder API and the underlying expression evaluation engine.
• One sentence: The programming language covered is Python, utilizing the purecloudplatformclientv2 SDK to validate the expression via the /api/v2/architect/expression/validate endpoint.

Prerequisites

• OAuth client type and required scopes: You need a Machine-to-Machine (M2M) OAuth client. The required scope for validating expressions is architect:expression:read. You will also need architect:flow:write if you intend to save the expression to a flow, but for this tutorial, validation is sufficient.
• SDK version or API version: Genesys Cloud Python SDK version 135.0.0 or later. The API version is v2.
• Language/runtime requirements: Python 3.8+.
• Any external dependencies: pip install purecloudplatformclientv2.

Authentication Setup

Genesys Cloud uses OAuth 2.0 for authentication. For server-side scripts and automated validation, the Client Credentials grant type is the standard approach. You must store your Client ID and Client Secret securely, typically in environment variables.

The following Python code initializes the SDK client and acquires an access token. It implements basic error handling for authentication failures (401 Unauthorized).

import os
import sys
from purecloudplatformclientv2 import (
    Configuration,
    ApiClient,
    PlatformApi,
    ArchitectExpressionApi
)
from purecloudplatformclientv2.rest import ApiException

def get_genesys_client() -> ApiClient:
    """
    Initializes and returns a configured Genesys Cloud API Client.
    Raises an exception if credentials are missing or invalid.
    """
    # Retrieve credentials from environment variables
    client_id = os.getenv("GENESYS_CLIENT_ID")
    client_secret = os.getenv("GENESYS_CLIENT_SECRET")
    
    if not client_id or not client_secret:
        raise EnvironmentError("GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET environment variables are required.")

    # Configure the OAuth2 client
    configuration = Configuration()
    configuration.client_id = client_id
    configuration.client_secret = client_secret
    
    # Initialize the API client
    api_client = ApiClient(configuration)
    
    # Platform API is used to refresh tokens if necessary, though M2M tokens 
    # are long-lived (1 hour) and do not require immediate refresh logic 
    # in simple scripts.
    platform_api = PlatformApi(api_client)
    
    try:
        # Attempt to fetch the token to ensure validity
        platform_api.get_platform_token()
    except ApiException as e:
        if e.status == 401:
            print("Authentication failed. Check your Client ID and Secret.", file=sys.stderr)
        elif e.status == 403:
            print("Access forbidden. The client may lack required scopes.", file=sys.stderr)
        else:
            print(f"Unexpected API error: {e}", file=sys.stderr)
        raise

    return api_client

# Initialize the client
api_client = get_genesys_client()

Implementation

Step 1: Understanding the Architect Expression Syntax

Architect expressions in Genesys Cloud are based on a subset of JavaScript syntax. They allow for string manipulation, mathematical operations, and conditional logic. To format a phone number from +1XXXXXXXXXX to (XXX) XXX-XXXX, you need to extract specific substrings and concatenate them with formatting characters.

The input string +1XXXXXXXXXX has a length of 12 characters.

• Index 0: +
• Index 1: 1
• Indices 2-4: Area Code (XXX)
• Indices 5-7: Prefix (XXX)
• Indices 8-11: Line Number (XXXX)

The target format (XXX) XXX-XXXX requires:

• Opening parenthesis (
• Area Code
• Closing parenthesis )
• Space
• Prefix
• Hyphen -
• Line Number

The core function in Architect expressions for substring extraction is substring(start, end). Note that substring is exclusive of the end index, similar to Python slicing.

The expression logic is:
"(" + substring(phoneNumber, 2, 5) + ") " + substring(phoneNumber, 5, 8) + "-" + substring(phoneNumber, 8)

However, Architect expressions do not support direct variable assignment in the same way JavaScript does. You typically use this expression within a Set Variable action or a Prompt action. For validation, we treat the expression as a string literal passed to the validator.

Step 2: Constructing the Expression Payload

To validate an expression, you must send a JSON payload to the /api/v2/architect/expression/validate endpoint. The payload requires:

1. expression: The string expression to evaluate.
2. variables: A dictionary of variables available to the expression. This is crucial because the expression references phoneNumber. You must provide a sample value for this variable to test the formatting.

The expression string itself must be properly escaped if you are constructing it programmatically, but when sending JSON, the string value is straightforward.

# Define the expression string
# We use raw strings or standard strings, ensuring quotes are handled correctly in JSON
expression_str = '"(" + substring(phoneNumber, 2, 5) + ") " + substring(phoneNumber, 5, 8) + "-" + substring(phoneNumber, 8)'

# Define the input variable for testing
# We use a standard E.164 format number
test_phone_number = "+12125551234"

# Construct the validation payload
validation_payload = {
    "expression": expression_str,
    "variables": {
        "phoneNumber": test_phone_number
    }
}

# Print the payload for debugging
import json
print("Validation Payload:")
print(json.dumps(validation_payload, indent=2))

Step 3: Validating the Expression via API

Now we use the ArchitectExpressionApi to validate the expression. This step confirms that the syntax is correct and, more importantly, that it produces the expected output given the sample input.

The post_architect_expression_validate method sends the payload and returns a response object containing the result (the evaluated value) and any errors.

def validate_phone_expression(api_client: ApiClient, expression: str, test_number: str) -> dict:
    """
    Sends an expression to the Genesys Cloud validator and returns the result.
    
    Args:
        api_client: The initialized ApiClient instance.
        expression: The Architect expression string.
        test_number: The sample phone number to use for validation.
        
    Returns:
        A dictionary containing the validation result and any errors.
    """
    architect_api = ArchitectExpressionApi(api_client)
    
    payload = {
        "expression": expression,
        "variables": {
            "phoneNumber": test_number
        }
    }
    
    try:
        # Call the validation endpoint
        # The API expects the body to be a ValidateExpressionRequest object, 
        # but the SDK often accepts a dict if configured correctly, or you can 
        # use the raw request method. For clarity, we use the typed method if available,
        # or construct the request body manually.
        
        # In purecloudplatformclientv2, the method is post_architect_expression_validate
        # It takes a ValidateExpressionRequest body.
        from purecloudplatformclientv2.models import ValidateExpressionRequest
        
        request_body = ValidateExpressionRequest(
            expression=expression,
            variables={"phoneNumber": test_number}
        )
        
        response = architect_api.post_architect_expression_validate(request_body)
        
        return {
            "success": True,
            "result": response.result,
            "errors": response.errors
        }
        
    except ApiException as e:
        return {
            "success": False,
            "status_code": e.status,
            "reason": e.reason,
            "body": e.body
        }

# Execute the validation
expression_to_test = '"(" + substring(phoneNumber, 2, 5) + ") " + substring(phoneNumber, 5, 8) + "-" + substring(phoneNumber, 8)'
result = validate_phone_expression(api_client, expression_to_test, "+12125551234")

if result["success"]:
    print(f"Validation Successful.")
    print(f"Input: +12125551234")
    print(f"Output: {result['result']}")
    if result['errors']:
        print(f"Warnings/Errors: {result['errors']}")
else:
    print(f"Validation Failed with status {result['status_code']}: {result['reason']}")
    print(f"Body: {result['body']}")

Step 4: Handling Edge Cases

The basic expression assumes a perfect 12-character E.164 string starting with +1. Real-world data is messy. You might encounter:

1. Numbers without the country code (10 digits).
2. Numbers with different country codes (e.g., +44...).
3. Empty or null values.

To make the expression robust, you can nest if statements or use tryCatch if supported, but Architect expressions have limited error handling capabilities. A safer approach is to validate the length first.

A more robust expression:
if(length(phoneNumber) == 12, "(" + substring(phoneNumber, 2, 5) + ") " + substring(phoneNumber, 5, 8) + "-" + substring(phoneNumber, 8), phoneNumber)

This checks if the length is 12. If yes, it formats it. If no, it returns the original number unchanged. This prevents runtime errors if a 10-digit number is passed.

Let us validate this robust version.

robust_expression = 'if(length(phoneNumber) == 12, "(" + substring(phoneNumber, 2, 5) + ") " + substring(phoneNumber, 5, 8) + "-" + substring(phoneNumber, 8), phoneNumber)'

# Test with valid 12-char number
result_valid = validate_phone_expression(api_client, robust_expression, "+12125551234")
print(f"Valid Input Result: {result_valid['result']}")

# Test with invalid 10-digit number
result_invalid = validate_phone_expression(api_client, robust_expression, "2125551234")
print(f"Invalid Input Result: {result_invalid['result']}")

Complete Working Example

The following script combines authentication, payload construction, and validation into a single runnable module. It tests both the basic and robust expressions against multiple test cases.

import os
import sys
import json
from purecloudplatformclientv2 import (
    Configuration,
    ApiClient,
    ArchitectExpressionApi
)
from purecloudplatformclientv2.rest import ApiException
from purecloudplatformclientv2.models import ValidateExpressionRequest

def main():
    # 1. Authentication
    client_id = os.getenv("GENESYS_CLIENT_ID")
    client_secret = os.getenv("GENESYS_CLIENT_SECRET")
    
    if not client_id or not client_secret:
        print("Error: Set GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET env vars.")
        sys.exit(1)

    configuration = Configuration()
    configuration.client_id = client_id
    configuration.client_secret = client_secret
    api_client = ApiClient(configuration)
    
    architect_api = ArchitectExpressionApi(api_client)

    # 2. Define Expressions
    # Basic formatting for E.164 +1XXXXXXXXXX
    basic_expr = '"(" + substring(phoneNumber, 2, 5) + ") " + substring(phoneNumber, 5, 8) + "-" + substring(phoneNumber, 8)'
    
    # Robust formatting with length check
    robust_expr = 'if(length(phoneNumber) == 12, "(" + substring(phoneNumber, 2, 5) + ") " + substring(phoneNumber, 5, 8) + "-" + substring(phoneNumber, 8), phoneNumber)'

    # 3. Define Test Cases
    test_cases = [
        {"name": "Standard E.164", "value": "+12125551234"},
        {"name": "10-Digit Number", "value": "2125551234"},
        {"name": "Empty String", "value": ""},
        {"name": "International (UK)", "value": "+442071234567"}
    ]

    # 4. Run Validation
    print("Validating Basic Expression:")
    print("-" * 50)
    for case in test_cases:
        try:
            request_body = ValidateExpressionRequest(
                expression=basic_expr,
                variables={"phoneNumber": case["value"]}
            )
            response = architect_api.post_architect_expression_validate(request_body)
            print(f"Input: {case['value']} -> Output: {response.result}")
            if response.errors:
                print(f"   Warning: {response.errors}")
        except ApiException as e:
            print(f"Input: {case['value']} -> Error: {e.status} {e.reason}")

    print("\nValidating Robust Expression:")
    print("-" * 50)
    for case in test_cases:
        try:
            request_body = ValidateExpressionRequest(
                expression=robust_expr,
                variables={"phoneNumber": case["value"]}
            )
            response = architect_api.post_architect_expression_validate(request_body)
            print(f"Input: {case['value']} -> Output: {response.result}")
            if response.errors:
                print(f"   Warning: {response.errors}")
        except ApiException as e:
            print(f"Input: {case['value']} -> Error: {e.status} {e.reason}")

if __name__ == "__main__":
    main()

Common Errors & Debugging

Error: 400 Bad Request - Invalid Expression

What causes it:
The expression syntax is incorrect. Common mistakes include:

• Using Python-style slicing phoneNumber[2:5] instead of substring(phoneNumber, 2, 5).
• Missing quotes around string literals.
• Unclosed parentheses.

How to fix it:
Review the expression string. Ensure all string literals are enclosed in double quotes "". Ensure all function calls have matching parentheses. Use the validate endpoint iteratively to isolate the syntax error.

Error: 401 Unauthorized

What causes it:
The OAuth token is invalid, expired, or the client credentials are incorrect.

How to fix it:
Verify that GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET are correct. Ensure the client has the architect:expression:read scope. If using a long-running process, implement token refresh logic (though M2M tokens last 1 hour).

Error: Runtime Error - Index Out of Bounds

What causes it:
The substring function is called on a string that is too short. For example, calling substring(phoneNumber, 2, 5) on a 3-character string will cause an error during evaluation.

How to fix it:
Use the if function to check the string length before attempting substring operations.

if(length(phoneNumber) > 10, substring(phoneNumber, 2, 5), phoneNumber)

Error: Result is Null or Undefined

What causes it:
The variable phoneNumber is not defined in the variables payload, or the value passed is null.

How to fix it:
Ensure the variables dictionary in the ValidateExpressionRequest includes the key phoneNumber with a string value.

Official References

• Architect Expression Validation API Documentation
• Genesys Cloud Python SDK Reference
• Architect Expression Syntax Guide